Transmission with simple planetary gear sets

ABSTRACT

A transmission includes a first simple planetary gear set having first, second, and third elements, the first element of the first gear set receiving rotational motion input to the transmission, and a second simple planetary gear set having first, second, and third elements, the first element of the second gear set outputting rotational motion from the transmission and the third element of the second gear set being connected to the third element of the first gear set. The elements of the first gear set include a sun gear, a first carrier, and a first ring gear, and the elements of the second gear set include a second sun gear, a second carrier, and a second ring gear. A first clutch selectively couples the second element of the first gear set to the second element of the second gear set. A second clutch selectively couples the first element of the first gear set to the second element of the second gear set. A third clutch selectively couples two elements selected from the group consisting of the first, second, and third elements of the first gear set and the third element of the second gear set. A first brake selectively brakes the second element of the second gear set, and a second brake selectively brakes the third element of the second gear set.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a transmission. More particularly, thepresent invention relates to a vehicle transmission including multipleplanetary gear sets.

2. Description of Related Art

Transmissions are a conventional component in most, if not all, vehiclespowered by internal combustion engines. Typical vehicle transmissionsare either manual, automatic, or combined manual and automatic. Whilevehicles having manual transmissions are relatively simple and allow forsignificant driver control, vehicles equipped with automatictransmissions are relatively easy to drive because they do not requireconstant shifting and clutch control.

Most automatic transmissions include one or more gearing structures,known as planetary gear sets. Two of the most common types of planetarygear sets are simple single pinion planetary gear sets and simple doublepinion planetary gear sets. FIG. 1 shows a schematic front view of asimple single pinion planetary gear set, and FIG. 2 shows a schematicfront view of a simple dual pinion planetary gear set.

As shown in FIG. 1, the single pinion planetary gear set has threedifferent elements including sun gear 10, carrier 12, and ring gear 14.A single set of pinion gears 16 are mounted for rotation on carrier 12at a common radial distance from sun gear 10. Pinion gears 16 have outergear teeth engaging both outer gear teeth on sun gear 10 and inner gearteeth on ring gear 14. Rotational motion input to either sun gear 10,carrier 12, or ring gear 14 causes relative rotation of each of theseelements, and the resulting rotation of the elements provides output forthe gear set. Selection of the particular number of gear teeth ordiameters for sun gear 10, carrier 12, and ring gear 14, and optionalbraking of sun gear 10, carrier 12, or ring gear 14, determines therelative rotational velocities of sun gear 10, carrier 12 and ring gear14 to allow for output of a variety of different rotational speedsand/or directions.

As shown in FIG. 2, the dual pinion planetary gear set is similar to thesingle pinion gear set, but includes a set of inner pinion gears 18mounted for rotation on carrier 12 at a common radial distance from sungear 10 and a set of outer pinion gears 20 mounted for rotation oncarrier 12 at a greater common distance from sun gear 10. Each innerpinion gear 18 has outer teeth engaging sun gear 10 and a respective oneof outer pinion gears 20, while outer pinion gears 20 have outer teethengaging both the outer teeth of inner pinion gears 18 and the innerteeth of ring gear 14. Operation of the dual pinion planetary gear setof FIG. 2 is similar to operation of the single pinion planetary gearset of FIG. 1--rotational motion is input to one of the sun gear 10,carrier 12, and ring gear 14, and the resulting rotational motion ofthese elements provides output.

To allow for a greater number of shifting speeds, designers havedeveloped transmissions having multiple planetary gear sets. FIG. 3shows a partial schematic side view of a prior art Ravigneauxtransmission structure having four driving speeds and reverse. As shownin FIG. 3, this transmission includes input shaft 22 for input ofrotational motion to the transmission, output shaft 24 for output ofrotational motion from the transmission, simple double pinion planetarygear set 30, simple single pinion planetary gear set 40, first clutch50, second clutch 52, third clutch 54, first brake 56, and second brake58.

Gear set 30 includes sun gear 32, carrier 34, and ring gear 36, and gearset 40 includes sun gear 42, carrier 44 directly connected to carrier 34of gear set 30, and ring gear 46 directly connected to ring gear 36 ofgear set 30. First clutch 50, second clutch 52, and third clutch 54selectively couple input shaft 22, respectively, to sun gear 32 of gearset 30, to carrier 34 of gear set 30 and carrier 44 of gear set 40, andto sun gear 42 of gear set 40. First brake 56 selectively brakesrotational motion of carrier 44 of gear set 40 and carrier 34 of gearset 30. Second brake 58 selectively brakes rotational motion of sun gear42 of gear set 40. Output shaft 24 is connected directly to both ringgear 46 of second gear set 40 and ring gear 36 of first gear set 30.

A controller (not shown) simultaneously activates two of clutches 50,52, and 54, or one of clutches 50, 52, and 54 and one of brakes 56 and58 to change speeds (gear ratios) of the transmission shown in FIG. 3.In a first driving speed of the transmission shown in FIG. 3, thecontroller activates (engages) first clutch 50 and first brake 56 sothat output shaft 24 rotates once for each 2.846 rotations of inputshaft 22. In a second driving speed, the controller activates firstclutch 50 and second brake 58 so that output shaft 24 rotates once foreach 1.581 rotations of input shaft 22. In a third driving speed, thecontroller activates first clutch 50 and second clutch 52 so that outputshaft 24 rotates once for each rotation of input shaft 22. In a fourthdriving speed, the controller activates second clutch 52 and secondbrake 58 so that output shaft 24 rotates once for each 0.685 rotationsof input shaft 22. In reverse, the controller activates third clutch 54and first brake 56 so that output shaft 24 rotates once, in a directionopposite to that of output shaft 24 rotation in the first through fourthdriving speeds, for each rotation of input shaft 22.

Transmissions including multiple planetary gear sets, such as thetransmission shown in FIG. 3, have been installed in a number ofdifferent types of vehicles. However, some of these complex transmissionstructures have one or more drawbacks. For example, transmissions withmore than one planetary gear set are sometimes noisy, large in size, anddifficult to manufacture.

Drag loss or friction loss is another significant disadvantage oftransmissions having a plurality of planetary gear sets. Friction lossreduces fuel economy and overall efficiency of a vehicle. This lossoccurs when engagement surfaces of a deactivated clutch or brake come incontact with rotating components. For example, when the transmission ofFIG. 3 is placed in the first driving speed, the second clutch 52, thirdclutch 54, and second brake 58 are deactivated and cause friction astransmission components rotate with respect to them.

FIG. 4 shows a table including the relative amounts of friction lossoccurring at clutches 50, 52, and 54 and at brakes 56 and 58 for each ofthe gear ratios of the transmission shown in FIG. 3. FIG. 4 also showsthe total relative amount of friction loss for each gear ratio of thetransmission and for each clutch 50, 52, 54 and brake 56 and 58 of thetransmission. The values shown in the table of FIG. 4 are directlyproportional to power loss. As is shown by the table of FIG. 4,frictional power loss occurs in each speed and in reverse for thetransmission shown in FIG. 3. If transmissions could be designed with areduced loss in even one gear ratio or at even one clutch or brake,vehicles equipped with these transmissions would be more fuel efficient.

In light of the foregoing, there is a need in the art for an improvedtransmission.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a transmission thatsubstantially obviates one or more of the limitations of the relatedart. In particular, the present invention is directed to an improvedtransmission having reduced friction loss. Preferably, the transmissionof the invention is relatively quiet, compact, and easy to manufacture.

To achieve these and other advantages and in accordance with the purposeof the invention, as embodied and broadly described herein, theinvention includes a transmission comprising a first simple planetarygear set having first, second, and third elements, the first element ofthe first gear set receiving rotational motion input to thetransmission, and a second simple planetary gear set having first,second, and third elements, the first element of the second gear setoutputting rotational motion from the transmission and the third elementof the second gear set being connected to the third element of the firstgear set. A first clutch selectively couples the second element of thefirst gear set to the second element of the second gear set. A secondclutch selectively couples the first element of the first gear set tothe second element of the second gear set. A third clutch selectivelycouples two elements selected from the group consisting of the first,second, and third elements of the first gear set and the third elementof the second gear set. A first brake selectively brakes the secondelement of the second gear set, and a second brake selectively brakesthe third element of the second gear set.

In another aspect, the elements of the first gear set include a sungear, a first carrier, and a first ring gear, and the elements of thesecond gear set include a second sun gear, a second carrier, and asecond ring gear.

In a further aspect, the first and second planetary gear sets are singlepinion or double pinion.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention. In the drawings,

FIG. 1 is a schematic front view of a prior art, simple, single pinionplanetary gear set;

FIG. 2 is a schematic front view of a prior art, simple, double pinionplanetary gear set;

FIG. 3 is a partial schematic side view of a prior art Ravigneauxtransmission structure having four driving speeds and reverse;

FIG. 4 is a table showing friction loss for the transmission of FIG. 3;

FIG. 5 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and first embodiment of thetransmission of the invention;

FIG. 6 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 5;

FIG. 7 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and second embodiment of thetransmission of the invention;

FIG. 8 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 7;

FIG. 9 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and third embodiment of thetransmission of the invention;

FIG. 10 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 9;

FIG. 11 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and fourth embodiment of thetransmission of the invention;

FIG. 12 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 11;

FIG. 13 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and fifth embodiment of thetransmission of the invention;

FIG. 14 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 13;

FIG. 15 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and sixth embodiment of thetransmission of the invention;

FIG. 16 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 15;

FIG. 17 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and seventh embodiment of thetransmission of the invention;

FIG. 18 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 17;

FIG. 19 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and eighth embodiment of thetransmission of the invention;

FIG. 20 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 19;

FIG. 21 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and ninth embodiment of thetransmission of the invention;

FIG. 22 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 21;

FIG. 23 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and tenth embodiment of thetransmission of the invention;

FIG. 24 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 23;

FIG. 25 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and eleventh embodiment of thetransmission of the invention;

FIG. 26 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 25;

FIG. 27 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and twelfth embodiment of thetransmission of the invention;

FIG. 28 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 27;

FIG. 29 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and thirteenth embodiment ofthe transmission of the invention;

FIG. 30 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 29;

FIG. 31 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and fourteenth embodiment ofthe transmission of the invention;

FIG. 32 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 31;

FIG. 33 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and fifteenth embodiment ofthe transmission of the invention;

FIG. 34 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 33;

FIG. 35 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and sixteenth embodiment ofthe transmission of the invention;

FIG. 36 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 35;

FIG. 37 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and seventeenth embodiment ofthe transmission of the invention;

FIG. 38 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 37;

FIG. 39 is a partial schematic side view of an internal combustionengine, torque converter, one-way clutch, and eighteenth embodiment ofthe transmission of the invention; and

FIG. 40 is a table showing the friction loss and reduction of frictionloss for the transmission of FIG. 39.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numbers areused in the drawings and the description to refer to the same or likeparts. In addition, reference numerals having the same final two digitsare used in the drawings and the description to refer to similar parts.

In accordance with the invention, there is provided a first simpleplanetary gear set having first, second, and third elements, and asecond planetary gear set having first second and third elements, thethird element of the second gear set being connected to the thirdelement of the first gear set. As shown in FIG. 5, a first embodiment ofthe invention includes first simple planetary gear set 130 and secondsimple planetary gear set 140. First gear set 130 is a single piniongear set, and elements of first gear set 130 include first sun gear 132,first carrier 134, and first ring gear 136. Second gear set 140 is asingle pinion gear set, and elements of second gear set 140 includesecond sun gear 142, second carrier 144, and second ring gear 146. Asshown in FIG. 5, first ring gear 136 is directly connected to second sungear 142. First sun gear 132 and first carrier 134 lack a directconnection to second sun gear 142, second carrier 144, and second ringgear 146.

Rotational motion is input to the transmission of FIG. 5 via input shaft122 connected to first sun gear 132. When the transmission of FIG. 5 isused as an automatic transmission in an automobile, a torque converter60 and one way clutch 62 transmit rotational motion from an internalcombustion engine 64 to input shaft 122.

Rotational motion is output from the transmission of FIG. 5 via outputshaft 124 connected to second ring gear 146. When the transmission ofFIG. 5 is used in an automobile, output shaft 124 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

In accordance with the invention, a first clutch selectively couples thesecond element of the first gear set to the second element of the secondgear set, a second clutch selectively couples the first element of thefirst gear set to the second element of the second gear set, a thirdclutch selectively couples two elements selected from the groupconsisting of the first, second, and third elements of the first gearset and the third element of the second gear set, a first brakeselectively brakes the second element of the second gear set, and asecond brake selectively brakes the third element of the second gearset. As shown in FIG. 5, the transmission of the first embodiment alsoincludes first clutch 150 selectively coupling first carrier 134 tosecond carrier 144, second clutch 152 selectively coupling first sungear 132 to second carrier 144, third clutch 154 selectively couplingfirst carrier 134 to first ring gear 136, first brake 156 selectivelybraking rotational motion of second carrier 144, and second brake 158selectively braking rotational motion of second sun gear 142.

To change speeds (gear ratios) of the transmission shown in FIG. 5, acontrol system (not shown) simultaneously activates (engages) two ofclutches 150, 152, and 154, or one of clutches 150, 152, and 154 and oneof brakes 156 and 158. In a first driving speed of the transmissionshown in FIG. 5, the controller activates first clutch 150 and firstbrake 156 so that output shaft 124 rotates slower than input shaft 122.In a second driving speed, the control system activates first clutch 150and second brake 158 so that output shaft 124 rotates slower than inputshaft 122, but relatively faster than when the transmission is in thefirst driving speed.

In a third driving speed, the control system activates first clutch 150and second clutch 152 so that output shaft 124 rotates once for eachrotation of input shaft 122. In a fourth driving speed, the controlsystem activates second clutch 152 and second brake 158 so that outputshaft 124 rotates faster than input shaft 122. In reverse, the controlsystem activates third clutch 154 and first brake 156 so that outputshaft 124 rotates at a rate slower than input shaft 122 and in adirection opposite to that of output shaft 124 in the first throughfourth driving speeds.

FIG. 6 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 150, 152, and154 and at brakes 156 and 158 for each of the gear ratios of thetransmission shown in FIG. 5. FIG. 6 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 150, 152, 154 and brake 156 and 158 of the transmission. Inaddition, the bottom row and right end column of the table include acomparison between the transmission shown in FIG. 5 and the prior arttransmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 6, the transmission of FIG. 5 has a 57% reduction in friction lossat first clutch 150, a 57% reduction in friction loss at third clutch154, a 28% reduction of friction loss in the first driving speed, a 28%reduction of friction loss in the second driving speed, a 40% reductionof friction loss in the fourth driving speed, a 30% reduction offriction loss in reverse, and a 28% overall reduction of friction loss.When the transmission of FIG. 5 is installed in a vehicle, thesereductions of friction loss significantly decrease the amount of powerloss and improve vehicle fuel efficiency.

One possible reason for the reduced friction loss in the transmission ofFIG. 5 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 7 shows a second embodiment of the transmission of the invention.The transmission shown in FIG. 7 includes first simple planetary gearset 230 and second simple planetary gear set 240. First gear set 230 isa single pinion gear set, and elements of first gear set 230 includefirst sun gear 232, first carrier 234, and first ring gear 236. Secondgear set 240 is a single pinion gear set, and elements of second gearset 240 include second sun gear 242, second carrier 244, and second ringgear 246. As shown in FIG. 7, first ring gear 236 is directly connectedto second sun gear 242. First sun gear 232 and first carrier 234 lack adirect connection to second sun gear 242, second carrier 244, and secondring gear 246.

Rotational motion is input to the transmission of FIG. 7 via input shaft222 connected to first sun gear 232. When the transmission of FIG. 7 isused as an automatic transmission in an automobile, a torque converter60 and one way clutch 62 transmit rotational motion from an internalcombustion engine 64 to the input shaft 222.

Rotational motion is output from the transmission of FIG. 7 via outputshaft 224 connected to second ring gear 246. When the transmission ofFIG. 7 is used in an automobile, output shaft 224 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 7, the transmission of the second embodiment alsoincludes first clutch 250 selectively coupling first carrier 234 tosecond carrier 244, second clutch 252 selectively coupling first sungear 232 to second carrier 244, third clutch 254 selectively couplingfirst sun gear 232 to first carrier 234, first brake 256 selectivelybraking rotational motion of second carrier 244, and second brake 258selectively braking rotational motion of the second sun gear 242.

To change speeds (gear ratios) of the transmission shown in FIG. 7, acontrol system (not shown) simultaneously activates (engages) two ofclutches 250, 252, and 254, or one of clutches 250, 252, and 254 and oneof brakes 256 and 258 and 254 and both of brakes 256 and 258. In a firstdriving speed of the transmission shown in FIG. 7, the controlleractivates first clutch 250 and first brake 256 so that output shaft 224rotates slower than input shaft 222. In a second driving speed, thecontrol system activates first clutch 250 and second brake 258 so thatoutput shaft 224 rotates slower than input shaft 222, but relativelyfaster than when the transmission is in the first driving speed.

In a third driving speed, the control system activates first clutch 250and second clutch 252 so that output shaft 224 rotates once for eachrotation of input shaft 222. In a fourth driving speed, the controlsystem activates second clutch 252 and second brake 258 so that outputshaft 224 rotates faster than input shaft 222. In reverse, the controlsystem activates third clutch 254 and first brake 256 so that outputshaft 224 rotates at a rate slower than input shaft 222 and in adirection opposite to that of output shaft 224 in the first throughfourth driving speeds.

FIG. 8 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 250, 252, and254 and at brakes 256 and 258 for each of the gear ratios of thetransmission shown in FIG. 7. FIG. 8 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 250, 252, 254 and brake 256 and 258 of the transmission. Inaddition, the bottom row and right end column of the table include acomparison between the transmission shown in FIG. 7 and the prior arttransmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 8, the transmission of FIG. 7 has a 57% reduction in friction lossat first clutch 250, a 57% reduction in friction loss at third clutch254, a 28% reduction of friction loss in the first driving speed, a 28%reduction of friction loss in the second driving speed, a 40% reductionof friction loss in the fourth driving speed, a 30% reduction offriction loss in reverse, and a 28% overall reduction of friction loss.When the transmission of FIG. 7 is installed in a vehicle, thesereductions of friction loss decrease the amount of power loss, andimprove vehicle fuel efficiency.

One possible reason for the decreased friction loss transmission of FIG.7 is because deactivated clutches and brakes are not positioned adjacentto the fastest rotating components of the transmission.

FIG. 9 shows a third embodiment of the transmission of the invention.The transmission shown in FIG. 9 includes first simple planetary gearset 330 and second simple planetary gear set 340. First gear set 330 isa single pinion gear set, and elements of first gear set 330 includefirst sun gear 332, first carrier 334, and first ring gear 336. Secondgear set 340 is a single pinion gear set, and elements of second gearset 340 include second sun gear 342, second carrier 344, and second ringgear 346. As shown in FIG. 9, first ring gear 336 is directly connectedto second sun gear 342. First sun gear 332 and first carrier 334 lack adirect connection to second sun gear 342, second carrier 344, and secondring gear 346.

Rotational motion is input to the transmission of FIG. 9 via input shaft322 connected to first sun gear 332. When the transmission of FIG. 9 isused as an automatic transmission in an automobile, a torque converter60 and one way clutch 62 transmit rotational motion from an internalcombustion engine 64 to the input shaft 322.

Rotational motion is output from the transmission of FIG. 9 via outputshaft 324 connected to second ring gear 346. When the transmission ofFIG. 9 is used in an automobile, output shaft 324 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 9, the transmission of the third embodiment alsoincludes first clutch 350 selectively coupling first carrier 334 tosecond carrier 344, second clutch 352 selectively coupling first sungear 332 to second carrier 344, third clutch 354 selectively couplingfirst sun gear 332 to second sun gear 342, first brake 356 selectivelybraking rotational motion of second sun gear 342, and second brake 358selectively braking rotational motion of the second carrier 344.

To change speeds (gear ratios) of the transmission shown in FIG. 9, acontrol system (not shown) simultaneously activates (engages) two ofclutches 350, 352, and 354, or one of clutches 350, 352, and 354 and oneof brakes 356 and 358. In a first driving speed of the transmissionshown in FIG. 9, the controller activates first clutch 350 and firstbrake 356 so that output shaft 324 rotates slower than input shaft 322.In a second driving speed, the control system activates first clutch 350and second brake 358 so that output shaft 324 rotates slower than inputshaft 322, but relatively faster than when the transmission is in thefirst driving speed.

In a third driving speed, the control system activates first clutch 350and second clutch 352 so that output shaft 324 rotates once for eachrotation of input shaft 322. In a fourth driving speed, the controlsystem activates second clutch 352 and second brake 358 so that outputshaft 324 rotates faster than input shaft 322. In reverse, the controlsystem activates third clutch 354 and first brake 356 so that outputshaft 324 rotates at a rate slower than input shaft 322 and in adirection opposite to that of output shaft 324 in the first throughfourth driving speeds.

FIG. 10 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 350, 352, and354 and at brakes 356 and 358 for each of the gear ratios of thetransmission shown in FIG. 9. FIG. 10 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 350, 352, 354 and brake 356 and 358 of the transmission. Inaddition, the bottom row and right end column of the table include acomparison between the transmission shown in FIG. 9 and the prior arttransmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 10, the transmission of FIG. 9 has a 57% reduction in friction lossat first clutch 350, a 22% reduction of friction loss in the fourthdriving speed, a 30% reduction of friction loss in reverse, and a 14%overall reduction of friction loss. When the transmission of FIG. 9 isinstalled in a vehicle, these reductions of friction loss decrease theamount of power loss and improve vehicle fuel efficiency.

One reason for the decreased friction loss in the transmission of FIG. 9is because deactivated clutches and brakes are not positioned adjacentto the fastest rotating components of the transmission.

FIG. 11 shows a fourth embodiment of the transmission of the invention.The transmission shown in FIG. 11 includes first simple planetary gearset 430 and second simple planetary gear set 440. First gear set 430 isa single pinion gear set, and elements of first gear set 430 includefirst sun gear 432, first carrier 434, and first ring gear 436. Secondgear set 440 is a double pinion gear set, and elements of second gearset 440 include second sun gear 442, second carrier 444, and second ringgear 446. As shown in FIG. 11, first ring gear 436 is directly connectedto second sun gear 432. First sun gear 432 and first carrier 434 lack adirect connection to second sun gear 442, second carrier 444, and secondring gear 446.

Rotational motion is input to the transmission of FIG. 11 via inputshaft 422 connected to first sun gear 432. When the transmission of FIG.11 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 422.

Rotational motion is output from the transmission of FIG. 11 via outputshaft 424 connected to second carrier 444. When the transmission of FIG.11 is used in an automobile, output shaft 424 is connected to a drivetrain (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 11, the transmission of the fourth embodiment alsoincludes first clutch 450 selectively coupling first carrier 434 tosecond ring gear 446, second clutch 452 selectively coupling first sungear 432 to second ring gear 436, third clutch 454 selectively couplingfirst carrier 434 to first sun gear 432, first brake 456 selectivelybraking rotational motion of second ring gear 446, and second brake 458selectively braking rotational motion of the second sun gear 442.

To change speeds (gear ratios) of the transmission shown in FIG. 11, acontrol system (not shown) simultaneously activates (engages) two ofclutches 450, 452, and 454, or one of clutches 450, 452, and 454 and oneof brakes 456 and 458. In a first driving speed of the transmissionshown in FIG. 11, the controller activates first clutch 450 and firstbrake 456 so that output shaft 424 rotates slower than input shaft 422.In a second driving speed, the control system activates first clutch 450and second brake 458 so that output shaft 424 rotates slower than inputshaft 422, but relatively faster than when the transmission is in thefirst driving speed.

In a third driving speed, the control system activates first clutch 450and second clutch 452 so that output shaft 424 rotates once for eachrotation of input shaft 422. In a fourth driving speed, the controlsystem activates second clutch 450 and second brake 458 so that outputshaft 424 rotates faster than input shaft 422. In reverse, the controlsystem activates third clutch 454 and first brake 456 so that outputshaft 424 rotates at a rate slower than input shaft 422 and in adirection opposite to that of output shaft 424 in the first throughfourth driving speeds.

FIG. 12 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 450, 452, and454 and at brakes 456 and 458 for each of the gear ratios of thetransmission shown in FIG. 11. FIG. 12 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 450, 452, 254 and brake 456 and 458 of the transmission. Inaddition, the bottom row and right end column of the table include acomparison between the transmission shown FIG. 11 and the prior arttransmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 12, the transmission of FIG. 11 has a 57% reduction in frictionloss at first clutch 450, a 43% reduction in friction loss at thirdclutch 454, a 22% reduction of friction loss in the first driving speed,a 22% reduction of friction loss in the second driving speed, a 36%reduction of friction loss in the fourth driving speed, a 30% reductionof friction loss in reverse, and a 24% overall reduction of frictionloss. When the transmission of FIG. 11 is installed in a vehicle, thesereductions of friction loss decrease the amount of power loss, andimprove vehicle fuel efficiency.

One reason for the reduced friction loss may also be reduced in thetransmission of FIG. 11 is because deactivated clutches and brakes arenot positioned adjacent to the fastest rotating components of thetransmission.

FIG. 13 shows a fifth embodiment of the transmission of the invention.The transmission shown in FIG. 13 includes first simple planetary gearset 530 and second simple planetary gear set 540. First gear set 530 isa single pinion gear set, and elements of first gear set 530 includefirst sun gear 532, first carrier 534, and first ring gear 536. Secondgear set 540 is a double pinion gear set, and elements of second gearset 540 include second sun gear 542, second carrier 544, and second ringgear 546. As shown in FIG. 13, first ring gear 536 is directly connectedto second sun gear 542. First sun gear 532 and first carrier 534 lack adirect connection to second sun gear 542, second carrier 544, and secondring gear 256.

Rotational motion is input to the transmission of FIG. 13 via inputshaft 522 connected to first sun gear 532. When the transmission of FIG.13 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 522.

Rotational motion is output from the transmission of FIG. 13 via outputshaft 524 connected to second carrier 544. When the transmission of FIG.13 is used in an automobile, output shaft 524 is connected to a drivetrain (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 13, the transmission of the fifth embodiment alsoincludes first clutch 550 selectively coupling first carrier 534 tosecond ring gear 546, second clutch 552 selectively coupling first sungear 532 to second ring gear 546, third clutch 554 selectively couplingfirst ring gear 536 to first carrier 534, first brake 556 selectivelybraking rotational motion of second ring gear 546, and second brake 558selectively braking rotational motion of the second sun gear 542.

To change speeds (gear ratios) of the transmission shown in FIG. 13, acontrol system (not shown) simultaneously activates (engages) two ofclutches 550, 552, and 554, or one of clutches 550, 552, and 554 and oneof brakes 556 and 558. In a first driving speed of the transmissionshown in FIG. 13, the controller activates first clutch 550 and firstbrake 556 so that output shaft 524 rotates slower than input shaft 522.In a second driving speed, the control system activates first clutch 550and second brake 558 so that output shaft 524 rotates slower than inputshaft 522, but relatively faster than when the transmission is in thefirst driving speed.

In a third driving speed, the control system activates first clutch 550and second clutch 552 so that output shaft 524 rotates once for eachrotation of input shaft 522. In a fourth driving speed, the controlsystem activates second clutch 552 and second brake 558 so that outputshaft 524 rotates faster than input shaft 522. In reverse, the controlsystem activates third clutch 554 and first brake 556 so that outputshaft 524 rotates at a rate slower than input shaft 522 and in adirection opposite to that of output shaft 524 in the first throughfourth driving speeds.

FIG. 14 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 550, 552, and554 and at brakes 556 and 558 for each of the gear ratios of thetransmission shown in FIG. 13. FIG. 14 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 550, 552, 554 and brake 556 and 558 of the transmission. Inaddition, the bottom row and right end column of the table include acomparison between the transmission shown in FIG. 13 and the prior arttransmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 14, the transmission of FIG. 13 has a 57% reduction in frictionloss at first clutch 550, a 57% reduction in friction loss at thirdclutch 554, a 28% reduction of friction loss in the first driving speed,a 28% reduction of friction loss in the second driving speed, a 40%reduction of friction loss in the fourth driving speed, a 30% reductionof friction loss in reverse, and a 28% overall reduction of frictionloss. When the transmission of FIG. 13 is installed in a vehicle, thesereductions of friction loss decrease the amount of power loss andimprove vehicle fuel efficiency.

One possible reason for the decreased friction loss may also be reducedin the transmission of FIG. 13 is because deactivated clutches andbrakes are not positioned adjacent to the fastest rotating components ofthe transmission.

FIG. 15 shows a sixth embodiment of the transmission of the invention.The transmission shown in FIG. 15 includes first simple planetary gearset 630 and second simple planetary gear set 640. First gear set 630 isa single pinion gear set, and elements of first gear set 630 includefirst sun gear 632, first carrier 634, and first ring gear 636. Secondgear set 640 is a double pinion gear set, and elements of second gearset 640 include second sun gear 642, second carrier 644, and second ringgear 646. As shown in FIG. 15, first ring gear 636 is directly connectedto second sun gear 642. First sun gear 632 and first carrier 634 lack adirect connection to second sun gear 642, second carrier 644, and secondring gear 646.

Rotational motion is input to the transmission of FIG. 15 via inputshaft 622 connected to first sun gear 632. When the transmission of FIG.15 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 622.

Rotational motion is output from the transmission of FIG. 15 via outputshaft 624 connected to second carrier 644. When the transmission of FIG.15 is used in an automobile, output shaft 624 is connected to a drivetrain (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 15, the transmission of the sixth embodiment alsoincludes first clutch 650 selectively coupling first carrier 634 tosecond ring gear 646, second clutch 652 selectively coupling first sungear 632 to second ring gear 646, third clutch 654 selectively couplingfirst sun gear 632 to second sun gear 642, first brake 656 selectivelybraking rotational motion of second ring gear 646, and second brake 658selectively braking rotational motion of the second sun gear 642.

To change speeds (gear ratios) of the transmission shown in FIG. 15, acontrol system (not shown) simultaneously activates (engages) two ofclutches 650, 652, and 654, or one of clutches 650, 652, and 654 and oneof brakes 656 and 658. In a first driving speed of the transmissionshown in FIG. 15, the controller activates first clutch 650 and firstbrake 656 so that output shaft 624 rotates slower than input shaft 622.In a second driving speed, the control system activates first clutch 650and second brake 658 so that output shaft 624 rotates slower than inputshaft 622, but relatively faster than when the transmission is in thefirst driving speed.

In a third driving speed, the control system activates first clutch 650and second clutch 652 so that output shaft 624 rotates once for eachrotation of input shaft 622. In a fourth driving speed, the controlsystem activates second clutch 652 and second brake 658 so that outputshaft 624 rotates faster than input shaft 622. In reverse, the controlsystem activates third clutch 654 and first brake 656 so that outputshaft 624 rotates at a rate slower than input shaft 622 and in adirection opposite to that of output shaft 624 in the first throughfourth driving speeds.

FIG. 16 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 650, 652, and654 and at brakes 656 and 658 for each of the gear ratios of thetransmission shown in FIG. 15. FIG. 16 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 650, 652, 654 and brake 656 and 658 of the transmission. Inaddition, the bottom row and right end column of the table include acomparison between the transmission shown in FIG. 15 and the prior arttransmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 16, the transmission of FIG. 15 has a 57% reduction in frictionloss at first clutch 650, a 22% reduction of friction loss in the fourthdriving speed, a 30% reduction of friction loss in reverse, and a 14%overall reduction of friction loss. When the transmission of FIG. 15 isinstalled in a vehicle, these reductions of friction loss decrease theamount of power loss and improve vehicle fuel efficiency.

One possible reason for the reduced friction loss in the transmission ofFIG. 15 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 17 shows a seventh embodiment of the transmission of the invention.The transmission shown in FIG. 17 includes first simple planetary gearset 730 and second simple planetary gear set 740. First gear set 730 isa double pinion gear set, and elements of first gear set 730 includefirst sun gear 732, first carrier 734, and first ring gear 736. Secondgear set 740 is a single pinion gear set, and elements of second gearset 740 include second sun gear 742, second carrier 744, and second ringgear 746. A shown in FIG. 17, first carrier 734 is directly connected tosecond sun gear 742. First sun gear 732 and first ring gear 736 lack adirect connection to second sun gear 742, second carrier 744, and secondring gear 746.

Rotational motion is input to the transmission of FIG. 17 via inputshaft 722 connected to first sun gear 732. When the transmission of FIG.17 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 722.

Rotational motion is output from the transmission of FIG. 17 via outputshaft 724 connected to second ring gear 746. When the transmission ofFIG. 17 is used in an automobile, output shaft 724 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 17, the transmission of the seventh embodiment alsoincludes first clutch 750 selectively coupling first ring gear 736 tosecond carrier 744, second clutch 752 selectively coupling first sungear 732 to second carrier 744, third clutch 754 selectively couplingfirst carrier 734 to first ring gear 736, first brake 756 selectivelybraking rotational motion of second carrier 744, and second brake 758selectively braking rotational motion of second sun gear 742.

To change speeds (gear ratios) of the transmission shown in FIG. 17, acontrol system (not shown) simultaneously activates (engages) two ofclutches 750, 752, and 754, or one of clutches 750, 752, and 754 and oneof brakes 756 and 758. In a first driving speed of the transmissionshown in FIG. 17, the controller activates first clutch 750 and firstbrake 756 so that output shaft 724 rotates slower than input shaft 722.In a second driving speed, the control system activates first clutch 750and second brake 758 so that output shaft 724 rotates slower than inputshaft 722, but relatively faster than when the transmission is in thefirst driving speed.

In a third driving speed, the control system activates first clutch 750and second clutch 752 so that output shaft 724 rotates once for eachrotation of input shaft 722. In a fourth driving speed, the controlsystem activates second clutch 752 and second brake 758 so that outputshaft 724 rotates faster than input shaft 722. In reverse, the controlsystem activates third clutch 754 and first brake 756 so that outputshaft 724 rotates at a rate slower than input shaft 722 and in adirection opposite to that of output shaft 724 in the first throughfourth driving speeds.

FIG. 18 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 750, 752, and754 and at brakes 756 and 758 for each of the gear ratios of thetransmission shown in FIG. 17. FIG. 18 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 750, 752, 754 and brake 756 and 758 of the transmission. Inaddition, the bottom row and right end column of the table include acomparison between the transmission shown in FIG. 17 and the prior arttransmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 18, the transmission of FIG. 17 has a 57% reduction in frictionloss at first clutch 750, a 57% reduction in friction loss at thirdclutch 754, a 28% reduction of friction loss in the first driving speed,a 28% reduction of friction loss in the second driving speed, a 40%reduction of friction loss in the fourth driving speed, a 30% reductionof friction loss in reverse, and a 28% overall reduction of frictionloss. When the transmission of FIG. 17 is installed in a vehicle, thesereductions of friction loss decrease the amount of power loss andimprove vehicle fuel efficiency.

One possible reason for the reduced friction loss in the transmission ofFIG. 17 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 19 shows an eighth embodiment of the transmission of the invention.The transmission shown in FIG. 19 includes first simple planetary gearset 830 and second simple planetary gear set 840. First gear set 830 isa double pinion gear set, and elements of first gear set 830 includefirst sun gear 832, first carrier 834, and first ring gear 836. Secondgear set 840 is a single pinion gear set, and elements of second gear,set 840 include second sun gear 842, second carrier 844, and second ringgear 846. As shown in FIG. 5, first carrier 834 is directly connected tosecond sun gear 842. First sun gear 832 and first ring gear 836 lack adirect connection to second sun gear 842, second carrier 844, and secondring gear 846.

Rotational motion is input to the transmission of FIG. 19 via inputshaft 822 connected to first sun gear 832. When the transmission of FIG.19 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 822.

Rotational motion is output from the transmission of FIG. 19 via outputshaft 824 connected to second ring gear 846. When the transmission ofFIG. 19 is used in an automobile, output shaft 824 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 19, the transmission of the eighth embodiment alsoincludes first clutch 850 selectively coupling first ring gear 836 tosecond carrier 844, second clutch 852 selectively coupling first sungear 832 to second carrier 844, third clutch 854 selectively couplingfirst sun gear 832 to first ring gear 836, first brake 856 selectivelybraking rotational motion of second carrier 844, and second brake 858selectively braking rotational motion of the second sun gear 842.

To change speeds (gear ratios) of the transmission shown in FIG. 19, acontrol system (not shown) simultaneously activates (engages) two ofclutches 850, 852, and 854, or one of clutches 850, 852, and 854 and oneof brakes 856 and 858. In a first driving speed of the transmissionshown in FIG. 19, the controller activates first clutch 850 and firstbrake 856 so that output shaft 824 rotates slower than input shaft 822.In at second driving speed, the control system activates first clutch850 and second brake 858 so that output shaft 824 rotates slower thaninput shaft 822, but relatively faster than when the transmission is inthe first driving speed.

In a third driving speed, the control system activates first clutch 850and second clutch 852 so that output shaft 824 rotates once for eachrotation of input shaft 822. In a fourth driving speed, the controlsystem activates second clutch 852 and second brake 858 so that outputshaft 824 rotates faster than input shaft 822. In reverse, the controlsystem activates third clutch 854 and first brake 856 so that outputshaft 824 rotates at a rate slower than input shaft 822 and in adirection opposite to that of output shaft 824 in the first throughfourth driving speeds.

FIG. 20 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 850, 852, and854 and at brakes 856 and 858 for each of the gear ratios of thetransmission shown in FIG. 19. FIG. 20 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 850, 852, 854 and brake 856 and 858 of the transmission. Inaddition, the bottom row and right end column of the table include acomparison between the transmission shown in FIG. 19 and the prior arttransmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 20, the transmission of FIG. 19 has a 57% reduction in frictionloss at first clutch 850, a 43% reduction in friction loss at thirdclutch 854, a 22% reduction of friction loss in the first driving speed,a 22% reduction of friction loss in the second driving speed, a 36%reduction of friction loss in the fourth driving speed, a 30% reductionof friction loss in reverse, and a 24% overall reduction of frictionloss. When the transmission of FIG. 19 is installed in a vehicle, thesereductions of friction loss decrease the amount of power loss andimprove vehicle fuel efficiency.

One possible reason for the reduced friction loss in the transmission ofFIG. 19 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 21 shows a ninth embodiment of the transmission of the invention.The transmission shown in FIG. 21 includes first simple planetary gearset 930 and second simple planetary gear set 940. First gear set 930 isa double pinion gear set, and elements of first gear set 930 includefirst sun gear 932, first carrier 934, and first ring gear 936. Secondgear set 940 is a single pinion gear set, and elements of second gearset 240 include second sun gear 942, second carrier 944, and second ringgear 946. As shown in FIG. 21, first carrier 934 is directly connectedto second sun gear 942. First sun gear 932 and first ring gear 936 lacka direct connection to second sun gear 942, second carrier 944, andsecond ring gear 946.

Rotational motion is input to the transmission of FIG. 21 via inputshaft 922 connected to first sun gear 932. When the transmission of FIG.21 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 922.

Rotational motion is output from the transmission of FIG. 21 via outputshaft 924 connected to second ring gear 946. When the transmission ofFIG. 21 is used in an automobile, output shaft 924 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 21, the transmission of the ninth embodiment alsoincludes first clutch 950 selectively coupling first ring gear 936 tosecond carrier 944, second clutch 952 selectively coupling first sungear 932 to second carrier 944, third clutch 954 selectively couplingfirst sun gear 932 to second sun gear 942, first brake 256 selectivelybraking rotational motion of second carrier 944, and second brake 958selectively braking rotational motion of the second sun gear 942.

To change speeds (gear ratios) of the transmission shown in FIG. 21, acontrol system (not shown) simultaneously activates (engages) two ofclutches 950, 952, and 954, or one of clutches 950, 952, and 954 and oneof brakes 956 and 958. In a first driving speed of the transmissionshown in FIG. 19, the controller activates first clutch 950 and firstbrake 956 so that output shaft 924 rotates slower than input shaft 922.In a second driving speed, the control system activates first clutch 950and second brake 958 so that output shaft 924 rotates slower than inputshaft 922, but relatively faster than when the transmission is in thefirst driving speed.

In a third driving speed, the control system activates first clutch 950and second clutch 952 so that output shaft 924 rotates once for eachrotation of input shaft 922. In a fourth driving speed, the controlsystem activates second clutch 952 and second brake 958 so that outputshaft 924 rotates faster than input shaft 922. In reverse, the controlsystem activates third clutch 954 and first brake 956 so that outputshaft 924 rotates at a rate slower than input shaft 922 and in adirection opposite to that of output shaft 924 in the first throughfourth driving speeds.

FIG. 22 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 950, 952, and954 and at brakes 956 and 958 for each of the gear ratios of thetransmission shown in FIG. 21. FIG. 22 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 950, 952, 954 and brake 956 and 958 of the transmission. Inaddition, the bottom row and right end column of the table include acomparison between the transmission shown in FIG. 21 and the prior arttransmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 22, the transmission of FIG. 21 has a 57% reduction in frictionloss at first clutch 950, a 22% reduction of friction loss in the fourthdriving speed, a 30% reduction of friction loss in reverse, and a 14%overall reduction of friction loss. When the transmission of FIG. 21 isinstalled in a vehicle, these reductions of friction loss decrease theamount of power loss and improve vehicle fuel efficiency.

One possible reason for the decreased friction loss in the transmissionof FIG. 21 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 23 shows a tenth embodiment of the transmission of the invention.The transmission shown in FIG. 23 includes first simple planetary gearset 1030 and second simple planetary gear set 1040. First gear set 1030is a double pinion gear set, and elements of first gear set 1030 includefirst sun gear 1032, first carrier 1034, and first rings gear 1036.Second gear set 1040 is a double pinion gear set, and elements of secondgear set 1040 include second sun gear 1042, second carrier 1044, andsecond ring gear 1046. As shown in FIG. 23, first carrier 1034 isdirectly connected to second sun gear 1042. First sun gear 1032 andfirst ring gear 1036 lack a direct connection to second sun gear 1042,second carrier 1044, and second ring gear 1046.

Rotational motion is input to the transmission of FIG. 23 via inputshaft 1022 connected to first sun gear 1032. When the transmission ofFIG. 23 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 1022.

Rotational motion is output from the transmission of FIG. 23 via outputshaft 1024 connected to second carrier 1044. When the transmission ofFIG. 23 is used in an automobile, output shaft 1024 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 23, the transmission of the tenth embodiment alsoincludes first clutch 1050 selectively coupling first ring gear 1036 tosecond ring gear 1046, second clutch 1052 selectively coupling first sungear 1032 to second ring gear 1046, third clutch 1054 selectivelycoupling first sun gear 1032 to second sun gear 1042, first brake 1056selectively braking rotational motion of second ring gear 1046, andsecond brake 1058 selectively braking rotational motion of the secondsun gear 1042.

To change speeds (gear ratios) of the transmission shown in FIG. 23, acontrol system (not shown) simultaneously activates (engages) two ofclutches 1050, 1052, and 1054, or one of clutches 1050, 1052, and 1054and one of brakes 1056 and 1058. In a first driving speed of thetransmission shown in FIG. 23, the controller activates first clutch1050 and first brake 1056 so that output shaft 1024 rotates slower thaninput shaft 1022. In a second driving speed, the control systemactivates first clutch 1050 and second brake 1058 so that output shaft1024 rotates slower than input shaft 1022, but relatively faster thanwhen the transmission is in the first driving speed.

In a third driving speed, the control system activates first clutch 1050and second clutch 1052 so that output shaft 1024 rotates once for eachrotation of input shaft 1022. In a fourth driving speed, the controlsystem activates second clutch 1052 and second brake 1058 so that outputshaft 224 rotates faster than input shaft 1022. In reverse, the controlsystem activates third clutch 1054 and first brake 1056 so that outputshaft 1024 rotates at a rate slower than input shaft 1022 and in adirection opposite to that of output shaft 1024 in the first throughfourth driving speeds.

FIG. 24 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 1050, 1052, and1054 and at brakes 1056 and 1058 for each of the gear ratios of thetransmission shown in FIG. 23. FIG. 24 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 1050, 1052, 1054 and brake 1056 and 1058 of thetransmission. In addition, the bottom row and right end column of thetable include a comparison between the transmission shown in FIG. 23 andthe prior art transmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 24, the transmission of FIG. 23 has a 57% reduction in frictionloss at first clutch 1050, a 22% reduction of friction loss in thefourth driving speed, a 30% reduction of friction loss in reverse, and a14% overall reduction of friction loss. When the transmission of FIG. 23is, installed in a vehicle, these reductions of friction loss decreasethe amount of power loss and improve vehicle fuel efficiency.

One possible reason for the decreased friction loss in the transmissionof FIG. 23 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 25 shows an eleventh embodiment of the transmission of theinvention. The transmission shown in FIG. 25 includes first simpleplanetary gear set 1130 and second simple planetary gear set 1140. Firstgear set 1130 is a double pinion gear set, and elements of first gearset 1130 include first sun gear 1132, first carrier 1134, and first ringgear 1136. Second gear set 1140 is a double pinion gear set, andelements of second gear set 1140 include second sun gear 1142, secondcarrier 1144, and second ring gear 1146. As shown in FIG. 25, first sungear 1132, first carrier 1134, and first ring gear 1136 lack a directconnection to second sun gear 1142, second carrier 1144, and second ringgear 1146.

Rotational motion is input to the transmission of FIG. 25 via inputshaft 1122 connected to first sun gear 1132. When the transmission ofFIG. 25 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 1122.

Rotational motion is output from the transmission of FIG. 25 via outputshaft 1124 connected to second carrier 1144. When the transmission ofFIG. 25 is used in an automobile, output shaft 1124 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 25, the transmission of the eleventh embodiment alsoincludes first clutch 1150 selectively coupling first ring gear 1136 tosecond ring gear 1146, second clutch 1152 selectively coupling first sungear 1132 to second ring gear 1146, third clutch 1154 selectivelycoupling first sun gear 1132 to first ring gear 1136, first brake 1156selectively braking rotational motion of second ring gear 1146, andsecond brake 1158 selectively braking rotational motion of the secondsun gear 1142.

To change speeds (gear ratios) of the transmission shown in FIG. 25, acontrol system (not shown) simultaneously activates (engages) two ofclutches 1150, 1152, and 1154, or one of clutches 1150, 1152, and 1154and one of brakes 1156 and 1158. In a first driving speed of thetransmission shown in FIG. 25, the controller activates first clutch1150 and first brake 1156 so that output shaft 1124 rotates slower thaninput shaft 1122. In a second driving speed, the control systemactivates first clutch 1150 and second brake 1158 so that output shaft1124 rotates slower than input shaft 1122, but relatively faster thanwhen the transmission is in the first driving speed.

In a third driving speed, the control system activates first clutch 1150and second clutch 1152 so that output shaft 1124 rotates once for eachrotation of input shaft 1122. In a fourth driving speed, the controlsystem activates second clutch 1154 and second brake 1158 so that outputshaft 1124 rotates faster than input shaft 1122. In reverse, the controlsystem activates third clutch 1154 and first brake 1156 so that outputshaft 1124 rotates at a rate slower than input shaft 1122 and in adirection opposite to that of output shaft 1124 in the first throughfourth driving speeds.

FIG. 26 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 1150, 152, and1154 and at brakes 1156 and 1158 for each of the gear ratios of thetransmission shown in FIG. 25. FIG. 26 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 1150, 1152, 1154 and brake 1156 and 1158 of thetransmission. In addition, the bottom row and right end column of thetable include a comparison between the transmission shown in FIG. 25 andthe prior art transmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 26, the transmission of FIG. 25 has a 57% reduction in frictionloss at first clutch 1150, a 43% reduction in friction loss at thirdclutch 1154, a 22% reduction of friction loss in the first drivingspeed, a 22% reduction of friction loss in the second driving speed, a36% reduction of friction loss in the fourth driving speed, a 30%reduction of friction loss in reverse, and a 24% overall reduction offriction loss. When the transmission of FIG. 25 is installed in avehicle, these reductions of friction loss decrease the amount of powerloss and improve vehicle fuel efficiency.

One possible reason for the decreased friction loss in the transmissionof FIG. 25 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 27 shows a twelfth embodiment of the transmission of the invention.The transmission shown in FIG. 27 includes first simple planetary gearset 1230 and second simple planetary gear set 1240. First gear set 1230is a double pinion gear set, and elements of first gear set 1230 includefirst sun gear 1232, first carrier 1234, and first ring gear 1236.Second gear set 1240 is a double pinion gear set, and elements of secondgear set 1240 include second sun gear 1242, second carrier 1244, andsecond ring gear 1246. As shown in FIG. 27, first carrier 1234 isdirectly connected to second sun gear 1242. First sun gear 1232 andfirst ring gear 1236 lack a direct connection to second sun gear 1242,second carrier 1244, and second ring gear 1246.

Rotational motion is input to the transmission of FIG. 27 via inputshaft 1222 connected to first sun gear 1232. When the transmission ofFIG. 27 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 1222.

Rotational motion is output from the transmission of FIG. 27 via outputshaft 1224 connected to second carrier 1244. When the transmission ofFIG. 27 is used in an automobile, output shaft 1224 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 27, the transmission of the twelfth embodiment alsoincludes first clutch 1250 selectively coupling first ring gear 1236 tosecond ring gear 1246, second clutch 1252 selectively coupling first sungear 1232 to second ring gear 1246, third clutch 1254 selectivelycoupling first sun gear 1232 to first carrier 1234, first brake 1256selectively braking rotational motion of second ring gear 1246, andsecond brake 1258 selectively braking rotational motion of the secondsun gear 1242.

To change speeds (gear ratios) of the transmission shown in FIG. 27, acontrol system (not shown) simultaneously activates (engages) all two ofclutches 1250, 1252, and 1254, or one of clutches 1250, 1252, and 1254and one of brakes 1256 and 1258. In a first driving speed of thetransmission shown in FIG. 27, the controller activates first clutch1250 and first brake 1256 so that output shaft 1224 rotates slower thaninput shaft 1222. In a second driving speed, the control systemactivates first clutch 250 and second brake 1258 so that output shaft1224 rotates slower than input shaft 1222, but relatively faster thanwhen the transmission is in the first driving speed.

In a third driving speed, the control system activates first clutch 1250and second clutch 1252 so that output shaft 1224 rotates once for eachrotation of input shaft 1222. In a fourth driving speed, the controlsystem activates second clutch 1252 and second brake 1258 so that outputshaft 1224 rotates faster than input shaft 1222. In reverse, the controlsystem activates second clutch 1252 and first brake 1256 so that outputshaft 1224 rotates at a rate slower than input shaft 1222 and in adirection opposite to that of output shaft 1224 in the first throughfourth driving speeds.

FIG. 28 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 1250, 1252, and1254 and at brakes 1256 and 1258 for each of the gear ratios of thetransmission shown in FIG. 27. FIG. 28 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 1250, 1252, 1254 and brake 1256 and 1258 of thetransmission. In addition, the bottom row and right end column of thetable include a comparison between the transmission shown in FIG. 27 andthe prior art transmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 28, the transmission of FIG. 27 has a 57% reduction in frictionloss at first clutch 1250, a 57% reduction in friction loss at thirdclutch 1254, a 28% reduction of friction loss in the first drivingspeed, a 28% reduction of friction loss in the second driving speed, a40% reduction of friction loss in the fourth driving speed, a 30%reduction of friction loss in reverse, and a 28% overall reduction offriction loss. When the transmission of FIG. 27 is installed in avehicle, these reductions of friction loss decrease the amount of powerloss and improve vehicle fuel efficiency.

One possible reason for the decreased friction loss in the transmissionof FIG. 27 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 29 shows a thirteenth embodiment of the transmission of theinvention. The transmission shown in FIG. 29 includes first simpleplanetary gear set 1330 and second simple planetary gear set 1340. Firstgear set 1330 is a double pinion gear set, and elements of first gearset 1330 include first sun gear 1332, first carrier 1334, and first ringgear 1336. Second gear set 1340 is a single pinion gear set, andelements of second gear set 1340 include second sun gear 1342, secondcarrier 1344, and second ring gear 1346. As shown in FIG. 29, first sungear 1332 is directly connected to second sun gear 1342. First carrier1334 and first ring gear 1336 lack a direct connection to second sungear 1342, second carrier 1344, and second ring gear 1346.

Rotational motion is input to the transmission of FIG. 29 via inputshaft 222 connected to first carrier 1334. When the transmission of FIG.29 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 1322.

Rotational motion is output from the transmission of FIG. 29 via outputshaft 1324 connected to second ring gear 1346. When the transmission ofFIG. 29 is used in an automobile, output shaft 1324 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 29, the transmission of the thirteenth embodiment alsoincludes first clutch 1350 selectively coupling first ring gear 1336 tosecond carrier 1344, second clutch 1352 selectively coupling firstcarrier 1334 to second carrier 1344, third clutch 1354 selectivelycoupling first sun gear 1332 to first ring gear 1336, first brake 1356selectively braking rotational motion of second carrier 1344, and secondbrake 1358 selectively braking rotational motion of the second sun gear1342.

To change speeds (gear ratios) of the transmission shown in FIG. 29, acontrol system (not shown) simultaneously activates (engages) two ofclutches 1350, 1352, and 1354, or one of clutches 1350, 1352, and 1354and one of brakes 1356 and 1358. In a first driving speed of thetransmission shown in FIG. 29, the controller activates first clutch1350 and first brake 1356 so that output shaft 1324 rotates slower thaninput shaft 1322. In a second driving speed, the control systemactivates first clutch 1350 and second brake 1358 so that output shaft1324 rotates slower than input shaft 1322, but relatively faster thanwhen the transmission is in the first driving speed.

In a third driving speed, the control system activates first clutch 1350and second clutch 1352, so that output shaft 1324 rotates once for eachrotation of input shaft 1322. In a fourth driving speed, the controlsystem activates second clutch 1352 and second brake 1358 so that outputshaft 1324 rotates faster than input shaft 1322. In reverse, the controlsystem activates third clutch 1354 and first brake 1356 so that outputshaft 1324 rotates at a rate slower than input shaft 1322 and in adirection opposite to that of output shaft 1324 in the first throughfourth driving speeds.

FIG. 30 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 1350, 1352, and1354 and at brakes 1356 and 1358 for each of the gear ratios of thetransmission shown in FIG. 29. FIG. 30 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 1350, 1352, 1354 and brake 1356 and 1358 of thetransmission. In addition, the bottom row and right end column of thetable include a comparison between the transmission shown in FIG. 29 andthe prior art transmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 30, the transmission of FIG. 29 has a 57% reduction in frictionloss at first clutch 1350, a 57% reduction in friction loss at thirdclutch 1354, a 28% reduction of friction loss in the first drivingspeed, a 28% reduction of friction loss in the second driving speed, a40% reduction of friction loss in the fourth driving speed, a 30%reduction of friction loss in reverse, and a 28% overall reduction offriction loss. When the transmission of FIG. 29 is installed in avehicle, these reductions of friction loss decrease the amount of powerloss and improve vehicle fuel efficiency.

One possible reason for the decreased friction loss in the transmissionof FIG. 29 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 31 shows a fourteenth embodiment of the transmission of theinvention. The transmission shown in FIG. 31 includes first simpleplanetary gear set 1430 and second simple planetary gear set 1440. Firstgear set 1430 is a double pinion gear set, and elements of first gearset 1430 include first sun gear 1432, first carrier 1434, and first ringgear 1436. Second gear set 1440 is a single pinion gear set, andelements of second gear set 1440 include second sun gear 1442, secondcarrier 1444, and second ring gear 1446. As shown in FIG. 31, first sungear 1432 is directly connected to second sun gear 1442. First carrier1434 and first ring gear 1436 lack a direct connection to second sungear 1442, second carrier 1444, and second ring gear 1446.

Rotational motion is input to the transmission of FIG. 31 via inputshaft 1422 connected to first carrier 1434. When the transmission ofFIG. 31 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 1422.

Rotational motion is output from the transmission of FIG. 31 via outputshaft 1424 connected to second ring gear 1446. When the transmission ofFIG. 31 is used in an automobile, output shaft 1424 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 31, the transmission of the fourteenth embodiment alsoincludes first clutch 1450 selectively coupling first ring gear 1436 tosecond carrier 1444, second clutch 1452 selectively coupling firstcarrier 1434 to second carrier 1444, third clutch 1454 selectivelycoupling first carrier 1434 to first ring gear 1436, first brake 1456selectively braking rotational motion of second carrier 1444, and secondbrake 1458 selectively braking rotational motion of the second sun gear1442.

To change speeds (gear ratios) of the transmission shown in FIG. 31, acontrol system (not shown) simultaneously activates (engages) two ofclutches 1450, 1452, and 1454, or one of clutches 1450, 1452, and 1454and one of brakes 1456 and 1458. In a first driving speed of thetransmission shown in FIG. 31, the controller activates first clutch1450 and first brake 1456 so that output shaft 1424 rotates slower thaninput shaft 1422. In a second driving speed, the control systemactivates first clutch 1450 and second brake 1458 so that output shaft1424 rotates slower than input shaft 1422, but relatively faster thanwhen the transmission is in the first driving speed.

In a third driving speed, the control system activates first clutch 1450and second clutch 1452 so that output shaft 1424 rotates once for eachrotation of input shaft 1422. In a fourth driving speed, the controlsystem activates second clutch 1352 and second brake 1458 so that outputshaft 1424 rotates faster than input shaft 1422. In reverse, the controlsystem activates third clutch 1454 and first brake 1456 so that outputshaft 1424 rotates at a rate slower than input shaft 1422 and in adirection opposite to that of output shaft 1424 in the first throughfourth driving speeds.

FIG. 32 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 1450, 1452, and1454 and at brakes 1456 and 1458 for each of the gear ratios of thetransmission shown in FIG. 31. FIG. 32 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 1450, 1452, 1454 and brake 1456 and 1458 of thetransmission. In addition, the bottom row and right end column of thetable include a comparison between the transmission shown in FIG. 31 andthe prior art transmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 32, the transmission of FIG. 31 has a 57% reduction in frictionloss at first clutch 1450, a 43% reduction in friction loss at thirdclutch 1454, a 22% reduction of friction loss in the first drivingspeed, a 36% reduction of friction loss in the second driving speed, a40% reduction of friction loss in the fourth driving speed, a 30%reduction of friction loss in reverse, and a 24% overall reduction offriction loss. When the transmission of FIG. 31 is installed in avehicle, these reductions of friction loss decrease the amount of powerloss and improve vehicle fuel efficiency.

One possible reason for the decreased friction loss in the transmissionof FIG. 31 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 33 shows a fifteenth embodiment of the transmission of theinvention. The transmission shown in FIG. 33 includes first simpleplanetary gear set 1530 and second simple planetary gear set 1540. Firstgear set 1530 is a double pinion gear set, and elements of first gearset 1530 include first sun gear 1532, first carrier 1534, and first ringgear 1536. Second gear set 1540 is a single pinion gear set, andelements of second gear set 1540 include second sun gear 1542, secondcarrier 1544, and second ring gear 1546. As shown in FIG. 33, first sungear 1532 is directly connected to second sun gear 1542. First carrier1534 and first ring gear 1536 lack a direct connection to second sungear 1542, second carrier 1544, and second ring gear 1546.

Rotational motion is input to the transmission of FIG. 33 via inputshaft 1522 connected to first carrier 1534. When the transmission ofFIG. 33 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 1522.

Rotational motion is output from the transmission of FIG. 33 via outputshaft 1524 connected to second ring gear 1546. When the transmission ofFIG. 33 is used in an automobile, output shaft 1524 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 33, the transmission of the fifteenth embodiment alsoincludes first clutch 1550 selectively coupling first ring gear 1536 tosecond carrier 1544, second clutch 1552 selectively coupling firstcarrier 1534 to second carrier 1544, third clutch 1554 selectivelycoupling first carrier 1534 to first sun gear 1532, first brake 1556selectively braking rotational motion of second carrier 1544, and secondbrake 1558 selectively braking rotational motion of the second sun gear1542.

To change speeds (gear ratios) of the transmission shown in FIG. 33, acontrol system (not shown) simultaneously activates (engages) two ofclutches 1550, 1552, and 1554, or one of clutches 1550, 1552, and 1554and one of brakes 1556 and 1558. In a first driving speed of thetransmission shown in FIG. 33, the controller activates first clutch1550 and first brake 1556 so that output shaft 1524 rotates slower thaninput shaft 1522. In a second driving speed, the control systemactivates first clutch 1550 and second brake 1558 so that output shaft1524 rotates slower than input shaft 1522, but relatively faster thanwhen the transmission is in the first driving speed.

In a third driving speed, the control system activates first clutch 1550and second clutch 1552 so that output shaft 1524 rotates once for eachrotation of input shaft 1522. In a fourth driving speed, the controlsystem activates second clutch 1552 and second brake 1558 so that outputshaft 1524 rotates faster than input shaft 1522. In reverse, the controlsystem activates third clutch 1554 and first brake 1556 so that outputshaft 1524 rotates at a rate slower than input shaft 1522 and in adirection opposite to that of output shaft 1524 in the first throughfourth driving speeds.

FIG. 34 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 1550, 1552, and1554 and at brakes 1556 and 1558 for each of the gear ratios of thetransmission shown in FIG. 33. FIG. 34 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 1550, 1552, 1554 and brake 1556 and 1558 of thetransmission. In addition, the bottom row and right end column of thetable include a comparison between the transmission shown in FIG. 33 andthe prior art transmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 34, the transmission of FIG. 33 has a 27% reduction in frictionloss at first clutch 1550, a 22% reduction of friction loss in thefourth driving speed, a 30% reduction of friction loss in reverse, and a14% overall reduction of friction loss. When the transmission of FIG. 33is installed in a vehicle, these reductions of friction loss decreasethe amount of power loss and improve vehicle fuel efficiency.

One possible reason for the decreased friction loss in the transmissionof FIG. 33 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 35 shows a sixteenth embodiment of the transmission of theinvention. The transmission shown in FIG. 35 includes first simpleplanetary gear set 1630 and second simple planetary gear set 1640. Firstgear set 1630 is a double pinion gear set, and elements of first gearset 1630 include first sun gear 1632, first carrier 1634, and first ringgear 1636. Second gear set 1640 is a double pinion gear set, andelements of second gear set 1440 include second sun gear 1642, secondcarrier 1644, and second ring gear 1646. As shown in FIG. 35, first sungear 1632 is directly connected to second sun gear 1642. First carrier1634 and first ring gear 1536 lack a direct connection to second sungear 1642, second carrier 1644, and second ring gear 1646.

Rotational motion is input to the transmission of FIG. 35 via inputshaft 1622 connected to first carrier 1634. When the transmission ofFIG. 35 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 1622.

Rotational motion is output from the transmission of FIG. 35 via outputshaft 1624 connected to second carrier 1644. When the transmission ofFIG. 35 is used in an automobile, output shaft 1624 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 35, the transmission of the sixteenth embodiment alsoincludes first clutch 1650 selectively coupling first carrier 1634 tosecond ring gear 1646, second clutch 1652 selectively coupling firstcarrier 1634 to second ring gear 1646, third clutch 1654 selectivelycoupling first carrier 1534 to first sun gear 1632, first brake 1656selectively braking rotational motion of second ring gear 1646, andsecond brake 1658 selectively braking rotational motion of the secondsun gear 1642.

To change speeds (gear ratios) of the transmission shown in FIG. 35, acontrol system (not shown) simultaneously activates (engages) two ofclutches 1650, 1652, and 1654, or one of clutches 1650, 1652, and 1654and one of brakes 1656 and 1558. In a first driving speed of thetransmission shown in FIG. 35, the controller activates first clutch1650 and first brake 1656 so that output shaft 1624 rotates slower thaninput shaft 1622. In a second driving speed, the control systemactivates first clutch 1650 and second brake 1658 so that output shaft1624 rotates slower than input shaft 1622, but relatively faster thanwhen the transmission is in the first driving speed.

In a third driving speed, the control system activates first clutch 1650and second clutch 1652 so that output shaft 1624 rotates once for eachrotation of input shaft 1622. In a fourth driving speed, the controlsystem activates second clutch 1652 and second brake 1658 so that outputshaft 1624 rotates faster than input shaft 1622. In reverse, the controlsystem activates third clutch 1654 and first brake 1656 so that outputshaft 1624 rotates at a rate slower than input shaft 1622 and in adirection opposite to that of output shaft 1624 in the first throughfourth driving speeds.

FIG. 36 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 1650, 1652, and1654 and at brakes 1656 and 1658 for each of the gear ratios of thetransmission shown in FIG. 35. FIG. 36 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 1650, 1652, 1654 and brake 1656 and 1658 of thetransmission. In addition, the bottom row and right end column of thetable include a comparison between the transmission shown in FIG. 35 andthe prior art transmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 36, the transmission of FIG. 35 has a 57% reduction in frictionloss at first clutch 1650, a 22% reduction of friction loss in thefourth driving speed, a 30% reduction of friction loss in reverse, and a14% overall reduction of friction loss. When the transmission of FIG. 35is installed in a vehicle, these reductions of friction loss decreasethe amount of power loss and improve vehicle fuel efficiency.

One possible reason for the decreased friction loss in the transmissionof FIG. 35 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

FIG. 37 shows a seventeenth embodiment of the transmission of theinvention. The transmission shown in FIG. 37 includes first simpleplanetary gear set 1730 and second simple planetary gear set 1740. Firstgear set 1730 is a double pinion gear set, and elements of first gearset 1730 include first sun gear 1732, first carrier 1734, and first ringgear 1736. Second gear set 1740 is a double pinion gear set, andelements of second gear set 1740 include second sun gear 1742, secondcarrier 1744, and second ring gear 1746. As shown in FIG. 37, first sungear 1732, first carrier 1734, and first ring gear 1736 lack a directconnection to second sun gear 1742, second carrier 1744, and second ringgear 1746.

Rotational motion is input to the transmission of FIG. 37 via inputshaft 1722 connected to first carrier 1734. When the transmission ofFIG. 37 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 1722.

Rotational motion is output from the transmission of FIG. 37 via outputshaft 1724 connected to second carrier 1744. When the transmission ofFIG. 37 is used in an automobile, output shaft 1724 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 37, the transmission of the seventeenth embodiment alsoincludes first clutch 1750 selectively coupling first ring gear 1736 tosecond ring gear 1746, second clutch 1752 selectively coupling firstcarrier 1734 to second ring gear 1746, third clutch 1754 selectivelycoupling first carrier 1734 to first ring gear 1736, first brake 1756selectively braking rotational motion of second ring gear 1746, andsecond brake 1758 selectively braking rotational motion of the secondsun gear 1742.

To change speeds (gear ratios) of the transmission shown in FIG. 37, acontrol system (not shown) simultaneously activates (engages) two ofclutches 1750, 1752, and 1754, or one of clutches 1750, 1752, and 1754and one of brakes 1756 and 1758. In a first driving speed of thetransmission shown in FIG. 35, the controller activates first clutch1750 and first brake 1756 so that output shaft 1724 rotates slower thaninput shaft 1722. In a second driving speed, the control systemactivates first clutch 1750 and second brake 1758 so that output shaft1724 rotates slower than input shaft 1722, but relatively faster thanwhen the transmission is in the first driving speed.

In a third driving speed, the control system activates first clutch 1750and second clutch 1752 so that output shaft 1724 rotates once for eachrotation of input shaft 1722. In a fourth driving speed, the controlsystem activates second clutch 1752 and second brake 1758 so that outputshaft 1724 rotates faster than input shaft 1722. In reverse, the controlsystem activates third clutch 1754 and first brake 1756 so that outputshaft 1724 rotates at a rate slower than input shaft 1722 and in adirection opposite to that of output shaft 1724 in the first throughfourth driving speeds.

FIG. 38 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 1750, 1752, and1754 and at brakes 1756 and 1758 for each of the gear ratios of thetransmission shown in FIG. 37. FIG. 38 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 1750, 1752, 1754 and brake 1756 and 1758 of thetransmission. In addition, the bottom row and right end column of thetable include a comparison between the transmission shown in FIG. 37 andthe prior art transmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 38, the transmission of FIG. 37 has a 57% reduction in frictionloss at first clutch 1750, a 43% reduction in friction loss at thirdclutch 1754, a 22% reduction of friction loss in the first drivingspeed, a 22% reduction of friction loss in the second driving speed, a46% reduction of friction loss in the fourth driving speed, a 30%reduction of friction loss in reverse, and a 24% overall reduction offriction loss. When the transmission of FIG. 37 is installed in avehicle, these reductions of friction loss decrease the amount of powerloss and improve vehicle fuel efficiency.

One possible reason for the decreased friction loss may also be reducedin the transmission of FIG. 37 is because deactivated clutches andbrakes are not positioned adjacent to the fastest rotating components ofthe transmission.

FIG. 39 shows an eighteenth embodiment of the transmission of theinvention. The transmission shown in FIG. 39 includes first simpleplanetary gear set 1830 and second simple planetary gear set 1840. Firstgear set 1830 is a double pinion gear set, and elements of first gearset 1830 include first sun gear 1832, first carrier 1834, and first ringgear 1836. Second gear set 1840 is a double pinion gear set, andelements of second gear set 1840 include second sun gear 1842, secondcarrier 1844, and second ring gear 1846. As shown in FIG. 39, first sungear 1832 is directly connected to second sun gear 1842. First carrier1834 and first ring gear 1836 lack a direct connection to second sungear 1842, second carrier 1844, and second ring gear 1846.

Rotational motion is input to the transmission of FIG. 39 via inputshaft 1822 connected to first carrier 1834. When the transmission ofFIG. 39 is used as an automatic transmission in an automobile, a torqueconverter 60 and one way clutch 62 transmit rotational motion from aninternal combustion engine 64 to the input shaft 1822.

Rotational motion is output from the transmission of FIG. 39 via outputshaft 1824 connected to second carrier 1844. When the transmission ofFIG. 39 is used in an automobile, output shaft 1824 is connected to adrive train (not shown) for driving the drive wheels of an automobile.

As shown in FIG. 39, the transmission of the eighteenth embodiment alsoincludes first clutch 1850 selectively coupling first ring gear 1836 tosecond ring gear 1846, second clutch 1852 selectively coupling firstcarrier 1834 to second ring gear 1846, third clutch 1854 selectivelycoupling first ring gear 1836 to first sun gear 1832, first brake 1856selectively braking rotational motion of second ring gear 1846, andsecond brake 1858 selectively braking rotational motion of the secondsun gear 1842.

To change speeds (gear ratios) of the transmission shown in FIG. 39, acontrol system (not shown) simultaneously activates (engages) two ofclutches 1850, 1852, and 1654, or one of clutches 1850, 1852, and 1854and one of brakes 1856 and 1858. In a first driving speed of thetransmission shown in FIG. 39, the controller activates first clutch1850 and first brake 1856 so that output shaft 1824 rotates slower thaninput shaft 1822. In a second driving speed, the control systemactivates first clutch 1850 and second brake 1858 so that output shaft1824 rotates slower than input shaft 1822, but relatively faster thanwhen the transmission is in the first driving speed.

In a third driving speed, the control system activates first clutch 1850and second clutch 1852, and third clutch 1854 so that output shaft 1824rotates once for each rotation of input shaft 1822. In a fourth drivingspeed, the control system activates second clutch 1852 and second brake1858 so that output shaft 1824 rotates faster than input shaft 1822. Inreverse, the control system activates third clutch 1854 and first brake1856 so that output shaft 1824 rotates at a rate slower than input shaft1822 and in a direction opposite to that of output shaft 1824 in thefirst through fourth driving speeds.

FIG. 40 is a table, similar to the table of FIG. 4, including therelative amounts of friction loss occurring at clutches 1850, 1852, and1854 and at brakes 1856 and 1858 for each of the gear ratios of thetransmission shown in FIG. 39. FIG. 40 also shows the total relativeamount of friction loss for each gear ratio of the transmission and foreach clutch 1850, 1852, 1854 and brake 1856 and 1858 of thetransmission. In addition, the bottom row and right end column of thetable include a comparison between the transmission shown in FIG. 39 andthe prior art transmission shown in FIG. 3.

As compared to the prior art transmission of FIG. 3, and as shown inFIG. 40, the transmission of FIG. 39 has a 57% reduction in frictionloss at first clutch 1850, a 57% reduction in friction loss at thirdclutch 1854, a 28% reduction of friction loss in the first drivingspeed, a 28% reduction of friction loss in the second driving speed, a40% reduction of friction loss in the fourth driving speed, a 30%reduction of friction loss in reverse, and a 28% overall reduction offriction loss. When the transmission of FIG. 39 is installed in avehicle, these reductions of friction loss decrease the amount of powerloss and improve vehicle fuel efficiency.

One possible reason for the decreased friction loss in the transmissionof FIG. 39 is because deactivated clutches and brakes are not positionedadjacent to the fastest rotating components of the transmission.

The brakes and clutches in each of the embodiments are preferablyconfigured so that they prevent slippage of respective components. Asshown in the drawings, the brakes preferably include a portion attachedto static structure of the transmission, such as the transmissioncasing, so that the brakes are capable of preventing rotational motionof respective components when they are activated (engaged). Although thedrawings schematically show disc clutches and disc brakes in each of theabove mentioned embodiments, any type of clutch or brake structure couldbe used in the practice of the invention. For example, one or more ofthe brakes could be band brakes.

Preferably, in each of the embodiments, the elements (first sun gear,first carrier, and first ring gear) of the first gear set and theelements (second sun gear, second carrier, and second ring gear) of thesecond gear set having a direct connection lack a clutch positionedbetween them.

Although the schematic drawings of each the embodiments show shaftsproviding input and output structures directly connected to the elementsof the gear sets, different types of input or output structures can beused. For example, one or more gears could be connected to or engagedwith the input element or output element of the gear sets to provide forrespective input or output of rotational motion.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

What is claimed is:
 1. A transmission comprising:a first simple, singlepinion, planetary gear set having first, second, and third elements, thefirst element of the first gear set receiving rotational motion input tothe transmission,the first element of the first gear set being a firstsun gear, the second element of the first gear set being a firstcarrier, and the third element of the first gear set being a first ringgear; a second simple, single pinion, planetary gear set having first,second, and third elements, the first element of the second gear setoutputting rotational motion from the transmission, the third element ofthe second gear set being connected to the third element of the firstgear set,the first element of the second gear set being a second ringgear, the second element of the second gear set being a second carrier,and the third element of the second gear set being a second sun gear; afirst clutch selectively coupling the second element of the first gearset to the second element of the second gear set; a second clutchselectively coupling the first element of the first gear set to thesecond element of the second gear set; a third clutch selectivelycoupling two elements selected from the group consisting of the thirdelement of the second gear set and the first, second, and third elementsof the first gear set; a first brake selectively braking the secondelement of the second gear set; and a second brake selectively brakingthe third element of the second gear set.
 2. The transmission of claim1, wherein the third clutch selectively couples the first element of thefirst gear set to the second element of the first gear set.
 3. Thetransmission of claim 1, wherein the third clutch selectively couplesthe first element of the first gear set to the third element of thefirst gear set.
 4. The transmission of claim 1, wherein the third clutchselectively couples the first element of the first gear set to the thirdelement of the second gear set.
 5. The transmission of claim 1, whereinthe third clutch selectively couples the second element of the firstgear set to the third element of the first gear set.
 6. A transmissioncomprising:a first simple, single pinion, planetary gear set havingfirst, second, and third elements, the first element of the first gearset receiving rotational motion input to the transmission,the firstelement of the first gear set being a first sun gear, the second elementof the first gear set being a first carrier, and the third element ofthe first gear set being a first ring gear; a second simple, doublepinion, planetary gear set having first, second, and third elements, thefirst element of the second gear set outputting rotational motion fromthe transmission, the third element of the second gear set beingconnected to the third element of the first gear set,the first elementof the second gear set being a second carrier, the second element of thesecond gear set being a second ring gear, and the third element of thesecond gear set being a second sun gear; a first clutch selectivelycoupling the second element of the first gear set to the second elementof the second gear set; a second clutch selectively coupling the firstelement of the first gear set to the second element of the second gearset; a third clutch selectively coupling two elements selected from thegroup consisting of the third element of the second gear set and thefirst, second, and third elements of the first gear set; a first brakeselectively braking the second element of the second gear set; and asecond brake selectively braking the third element of the second gearset.
 7. The transmission of claim 6, wherein the third clutchselectively couples the first element of the first gear set to thesecond element of the first gear set.
 8. The transmission of claim 6,wherein the third clutch selectively couples the first element of thefirst gear set to the third element of the first gear set.
 9. Thetransmission of claim 6, wherein the third clutch selectively couplesthe first element of the first gear set to the third element of thesecond gear set.
 10. The transmission of claim 6, wherein the thirdclutch selectively couples the second element of the first gear set tothe third element of the first gear set.
 11. A transmission comprising:afirst simple, double pinion, planetary gear set having first, second,and third elements, the first element of the first gear set receivingrotational motion input to the transmission,the first element of thefirst gear set being a first sun gear, the second element of the firstgear set being a first ring gear, and the third element of the firstgear set being a first carrier; a second simple, double pinion,planetary gear set having first, second, and third elements, the firstelement of the second gear set outputting rotational motion from thetransmission, the third element of the second gear set being connectedto the third element of the first gear set,the first element of thesecond gear set being a second carrier, the second element of the secondgear set being a second ring gear, and the third element of the secondgear set being a second sun gear; a first clutch selectively couplingthe second element of the first gear set to the second element of thesecond gear set; a second clutch selectively coupling the first elementof the first gear set to the second element of the second gear set; athird clutch selectively coupling two elements selected from the groupconsisting of the third element of the second gear set and the first,second, and third elements of the first gear set; a first brakeselectively braking the second element of the second gear set; and asecond brake selectively braking the third element of the second gearset.
 12. The transmission of claim 11, wherein the third clutchselectively couples the first element of the first gear set to thesecond element of the first gear set.
 13. The transmission of claim 11,wherein the third clutch selectively couples the first element of thefirst gear set to the third element of the first gear set.
 14. Thetransmission of claim 11, wherein the third clutch selectively couplesthe first element of the first gear set to the third element of thesecond gear set.
 15. The transmission of claim 11, wherein the thirdclutch selectively couples the second element of the first gear set tothe third element of the first gear set.
 16. A transmission comprising:afirst simple, double pinion, planetary gear set having first, second,and third elements, the first element of the first gear set receivingrotational motion input to the transmission,the first element of thefirst gear set being a first carrier, the second element of the firstgear set being a first ring gear, and the third element of the firstgear set being a first sun gear; a second simple, double pinion,planetary gear set having first, second, and third elements, the firstelement of the second gear set outputting rotational motion from thetransmission, the third element of the second gear set being connectedto the third element of the first gear set,the first element of thesecond gear set being a second carrier, the second element of the secondgear set being a second ring gear, and the third element of the secondgear set being a second sun gear; a first clutch selectively couplingthe second element of the first gear set to the second element of thesecond gear set; a second clutch selectively coupling the first elementof the first gear set to the second element of the second gear set; athird clutch selectively coupling two elements selected from the groupconsisting of the third element of the second gear set and the first,second, and third elements of the first gear set; a first brakeselectively braking the second element of the second gear set; and asecond brake selectively braking the third element of the second gearset.
 17. The transmission of claim 16, wherein the third clutchselectively couples the first element of the first gear set to thesecond element of the first gear set.
 18. The transmission of claim 16,wherein the third clutch selectively couples the first element of thefirst gear set to the third element of the first gear set.
 19. Thetransmission of claim 16, wherein the third clutch selectively couplesthe first element of the first gear set to the third element of thesecond gear set.
 20. The transmission of claim 16, wherein the thirdclutch selectively couples the second element of the first gear set tothe third element of the first gear set.
 21. A transmission comprising:afirst simple planetary gear set having first, second, and thirdelements, the first element of the first gear set receiving rotationalmotion input to the transmission; a second simple planetary gear sethaving first, second, and third elements, the first element of thesecond gear set outputting rotational motion from the transmission andthe third element of the second gear set being connected to the thirdelement of the first gear set; a first clutch selectively coupling thesecond element of the first gear set to the second element of the secondgear set; a second clutch selectively coupling the first element of thefirst gear set to the second element of the second gear set; a thirdclutch selectively coupling the first element of the first gear set tothe second element of the first gear set; a first brake selectivelybraking the second element of the second gear set; and a second brakeselectively braking the third element of the second gear set.
 22. Thetransmission of claim 21, wherein the elements of the first gear setinclude a first sun gear, a first carrier, and a first ring gear, andthe elements of the second gear set include a second sun gear, a secondcarrier, and a second ring gear.
 23. A transmission comprising:a firstsimple planetary gear set having first, second, and third elements, thefirst element of the first gear set receiving rotational motion input tothe transmission; a second simple planetary gear set having first,second, and third elements the first element of the second gear setoutputting rotational motion from the transmission and the third elementof the second gear set being connected to the third element of the firstgear set; a first clutch selectively coupling the second element of thefirst gear set to the second element of the second gear set; a secondclutch selectively coupling the first element of the first gear set tothe second element of the second gear set; a third clutch selectivelycoupling the second element of the first gear set to the third elementof the first gear set; a first brake selectively braking the secondelement of the second gear set; and a second brake selectively brakingthe third element of the second gear set.
 24. The transmission of claim23, wherein the elements of the first gear set include a first sun gear,a first carrier, and a first ring gear, and the elements of the secondgear set include a second sun gear, a second carrier, and a second ringgear.
 25. A transmission comprising:a first simple, double pinion,planetary gear set having first, second, and third elements, the firstelement of the first gear set receiving rotational motion input to thetransmission,the first element of the first gear set being a first sungear, the second element of the first gear set being a first ring gear,and the third element of the first gear set being a first carrier; asecond simple, single pinion, planetary gear set having first, second,and third elements, the first element of the second gear set outputtingrotational motion from the transmission, the third element of the secondgear set being connected to the third element of the first gear set,thefirst element of the second gear set being a second ring gear, thesecond element of the second gear set being a second carrier, and thethird element of the second gear set being a second sun gear; a firstclutch selectively coupling the second element of the first gear set tothe second element of the second gear set; a second clutch selectivelycoupling the first element of the first gear set to the second elementof the second gear set; a third clutch selectively coupling the firstelement of the first gear set to the second element of the first gearset; a first brake selectively braking the second element of the secondgear set; and a second brake selectively braking the third element ofthe second gear set.
 26. A transmission comprising:a first simple,double pinion, planetary gear set having first, second, and thirdelements, the first element of the first gear set receiving rotationalmotion input to the transmission,the first element of the first gear setbeing a first sun gear, the second element of the first gear set being afirst ring gear, and the third element of the first gear set being afirst carrier; a second simple, single pinion, planetary gear set havingfirst, second, and third elements, the first element of the second gearset outputting rotational motion from the transmission, the thirdelement of the second gear set being connected to the third element ofthe first gear set,the first element of the second gear set being asecond ring gear, the second element of the second gear set being asecond carrier, and the third element of the second gear set being asecond sun gear; a first clutch selectively coupling the second elementof the first gear set to the second element of the second gear set; asecond clutch selectively coupling the first element of the first gearset to the second element of the second gear set; a third clutchselectively coupling the second element of the first gear set to thethird element of the first gear set; a first brake selectively brakingthe second element of the second gear set; and a second brakeselectively braking the third element of the second gear set.
 27. Atransmission comprising:a first simple, double pinion, planetary gearset having first, second, and third elements, the first element of thefirst gear set receiving rotational motion input to the transmission,thefirst element of the first gear set being a first carrier, the secondelement of the first gear set being a first ring gear, and the thirdelement of the first gear set being a first sun gear; a second simple,single pinion, planetary gear set having first, second, and thirdelements, the first element of the second gear set outputting rotationalmotion from the transmission, the third element of the second gear setbeing connected to the third element of the first gear set,the firstelement of the second gear set being a second ring gear, the secondelement of the second gear set being a second carrier, and the thirdelement of the second gear set being a second sun gear; a first clutchselectively coupling the second element of the first gear set to thesecond element of the second gear set; a second clutch selectivelycoupling the first element of the first gear set to the second elementof the second gear set; a third clutch selectively coupling the thirdclutch selectively couples the first element of the first gear set tothe second element of the first gear set; a first brake selectivelybraking the second element of the second gear set; and a second brakeselectively braking the third element of the second gear set.
 28. Atransmission comprising:a first simple, double pinion, planetary gearset having first, second, and third elements, the first element of thefirst gear set receiving rotational motion input to the transmission,thefirst element of the first gear set being a first carrier, the secondelement of the first gear set being a first ring gear, and the thirdelement of the first gear set being a first sun gear; a second simple,single pinion, planetary gear set having first, second, and thirdelements, the first element of the second gear set outputting rotationalmotion from the transmission, the third element of the second gear setbeing connected to the third element of the first gear set,the firstelement of the second gear set being a second ring gear, the secondelement of the second gear set being a second carrier, and the thirdelement of the second gear set being a second sun gear; a first clutchselectively coupling the second element of the first gear set to thesecond element of the second gear set; a second clutch selectivelycoupling the first element of the first gear set to the second elementof the second gear set; a third clutch selectively coupling the secondelement of the first gear set to the third element of the first gearset; a first brake selectively braking the second element of the secondgear set; and a second brake selectively braking the third element ofthe second gear set.